Sensor for Determining a Position of a Jack Element

ABSTRACT

In one aspect of the present invention, a drill string has a drill bit with a body intermediate a shank and a working face. The working face has at least one cutting element and a jack element disposed partially within the drill bit body substantially protruding from the working face. The jack element is adapted to rotate with respect to the bit body by a turbine disposed within a bore of the drill string. A generator with a rotor incorporated into a torque transmitting mechanism links the turbine to the jack element. When the jack element rotates, at least one waveform is produced in the generator. The waveform is processed by an electronic processing device to determine the rotational position of the jack element.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent application Ser. No. 11/851,095, which is herein incorporated by reference for all that it discloses.

BACKGROUND OF THE INVENTION

The present invention relates to the field of downhole oil, gas, and/or geothermal exploration and more particularly to the field of drill bits for aiding such exploration and drilling. Drill bits use rotary energy provided by the drill string to cut through downhole formations and advance the tool string further into the earth Often, the drill string is directed along complex drilling trajectories to maximize drilling resources and save drilling costs.

U.S. Pat. No. 5,803,185 to Barr et at which is herein incorporated by reference for all that it contains, discloses a steerable rotary drilling system with a bottom hole assembly which includes, in addition to the drill bit, a modulated bias unit and a control unit, the bias unit comprising a number of hydraulic actuators around the periphery of the unit, each having a movable thrust member which is hydraulically displaceable outwardly for engagement with the formation of the borehole being drilled. Each actuator may be connected, through a control valve, to a source of drilling fluid under pressure and the operation of the valve is controlled by the control unit so as to modulate the fluid pressure supplied to the actuators as the bias unit rotates. If the control valve is operated in synchronism with rotation of the bias unit the thrust members impart a lateral bias to the bias unit, and hence to the drill bit, to control the direction of drilling.

U.S. Pat. No. 6,150,822 to Hong, et al., which is herein incorporated by reference for all that it contains, discloses a microwave frequency range sensor (antenna or wave guide) disposed in the face of a diamond or PDC drill bit configured to minimize invasion of drilling fluid into the formation ahead of the bit. The sensor is connected to an instrument disposed in a sub interposed in the drill stem for generating and measuring the alteration of microwave energy.

U.S. Pat. No. 6,814,162 to Moran, et al., which is herein incorporated by reference for all that it contains, discloses a drill bit, comprising a bit body, a sensor disposed in the bit body, a single journal removably mounted to the bit body, and a roller cone rotatably mounted to the single journal. The drill bit may also comprise a short-hop telemetry transmission device adapted to transmit data from the sensor to a measurement-while-drilling device located above the drill bit on the drill string.

U.S. Pat. No. 5,415,030 to Jogi, et al., which is herein incorporated by reference for all that it contains, discloses a method for evaluating formations and bit conditions. The invention processes signals indicative of downhole weight on bit (WOB), downhole torque (TOR), rate of penetration (ROP), and bit rotations (RPM), while taking into account bit geometry to provide a plurality of well logs and to optimize the drilling process.

U.S. Pat. No. 5,363,926 to Mizuno, which is herein incorporated by reference for all that it contains, discloses a device for detecting inclination of a boring head of a boring tool.

The prior art also discloses devices adapted to steer the direction of penetration of a drill string. U.S. Pat. No. 6,913,095 to Krueger, U.S. Pat. No. 6,092,610 to Kosmala, et al., U.S. Pat. No. 6,581,699 to Chen, et al., U.S. Pat. No. 2,498,192 to Wright, U.S. Pat. No. 6,749,031 to Klemm, U.S. Pat. No. 7,013,994 to Eddison, which are all herein incorporated by reference for all that they contain, discloses directional drilling systems.

BRIEF SUMMARY OF THE INVENTION

In one aspect of the present invention, a drill string has a drill bit with a body intermediate a shank and a working face. The working face has at least one cutting element and a jack element disposed partially within the drill bit body substantially protruding from the working face. The jack element is adapted to rotate with respect to the bit body by a turbine disposed within a bore of the drill string. A generator with a rotor incorporated into a torque transmitting mechanism links the turbine to the jack element. When the jack element rotates, at least one waveform is produced in the generator. The waveform is processed by an electronic processing device to determine the rotational position of the jack element.

The electronic processing device may be incorporated in the drill bit, the drill string, or a remote location in electric communication with a telemetry system of the drill string. The torque transmitting mechanism may be a shaft that connects the jack element to the turbine. The torque transmitting mechanism may comprise a gear assembly. The gear assembly may comprise a gear ratio of20:1 to 30:1.

The drill string may comprise a position feedback sensor in electrical communication with the electronic processing device. The position feedback sensor may comprise at least two magnetically sensitive components, a pressure resistant material, an optical encoder, And/or a mechanical switch. At least one of the two magnetically sensitive components may be disposed on the torque transmitting mechanism. At least one of the two magnetically sensitive components may be disposed proximate the torque transmitting mechanism. At least one of the two magnetically sensitive components may comprise a magnet and/or a hall effect sensor. At least one of the two magnetically sensitive components may be powered by a downhole electrical source.

The rotation of the jack element may comprise a first angular velocity while a rotation of the drill bit comprises a second angular velocity. The first and second angular velocities may be substantially equal in magnitude and opposite in direction. The rotational position may be a relative rotational position determined by the electronic processing device. The electronic processing device may be a microcontroller.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional diagram of an embodiment of a derrick and downhole drill string.

FIG. 2 is a cross-sectional diagram of an embodiment of a portion of a downhole drill string.

FIG. 3 is a cross-sectional diagram of another embodiment of a portion of a downhole drill string.

FIG. 4 is a cross-sectional diagram of another embodiment of a portion of a downhole drill string.

FIG. 5 is a cross-sectional diagram of another embodiment of a portion of a downhole drill string.

FIG. 6 a is a diagram of an embodiment of a waveform.

FIG. 6 b is a diagram of another embodiment of a waveform.

FIG. 7 is a cross-sectional diagram of an embodiment of a telemetry system.

FIG. 8 is a cross-sectional diagram of another embodiment of a portion of a downhole drill string.

FIG. 9 is a cross-sectional diagram of another embodiment of a portion of a downhole drill string.

DETAILED DESCRIPTION OF THE INVENTION AND THE PREFERRED EMBODIMENT

FIG. 1 is a perspective diagram of an embodiment of a drill string 100 suspended by a derrick 101. A bottom-hole assembly 102 is located at the end of the drill string 100 and may be at the bottom of a wellbore 103. The drill string 100 may comprise a drill bit 104. As the drill bit 104 rotates downhole the drill string 100 advances farther into the earth. The drill string 100 may penetrate soft and/or hard subterranean formations 105. The drill bit 104 may be adapted to steer the drill string 100 in a desired trajectory. The bottomhole assembly 102 and/or downhole components may comprise data acquisition devices which may gather data. The data may be sent to the surface via a transmission system to a data swivel 106. The data swivel 106 may send the data to the surface equipment. Further, the surface equipment may send data and/or power to downhole tools and/or the bottomhole assembly 102. U.S. Pat. No. 6,670,880 which is herein incorporated by reference for all that it contains, discloses a telemetry system that may be compatible with the present invention; however, other forms of telemetry may also be compatible such as systems that include mud pulse systems, electromagnetic waves, radio waves, and/or short hop. In some embodiments, no telemetry system is incorporated into the drill string.

Referring now to FIG. 2, a cross-sectional diagram of a drill string 100 discloses a bottomhole assembly (BRA) 102. A jack element 201 may protrude beyond the working face of the drill bit. The jack element 201 may rotate around an axis independent of the drill bit and may be used for steering the drill string. The drill string comprises at least one position feedback sensor 202 that is adapted to detect a position and/or orientation of the jack element 201. Rotation of the jack element 201 may be powered by a driving mechanism, such as a downhole turbine 211 and/or generator 203.

A power source 204 may provide electricity to a direction and inclination (D&I) package 207. D&I package 207 may monitor the orientation of the BHA 102 with respect to some relatively constant object, such as the center of the planet, the moon, the surface of the planet, a satellite, or combinations thereof. A second power source 205 may provide electrical power to an electronic processing device 208. The electronic processing device may be incorporated in the drill bit 104, the drill string 100, or a remote location in electric communication with a telemetry system of the drill string 100. The electronic processing device 208 may be a microcontroller. The electronic processing device 208 may control steering and/or motor functions. The electronic processing device 208 may receive drill string orientation information from the D&I package 207 and may alter the speed or direction of the turbine 211 and/or generator 203.

In the present embodiment, a jack assembly 301, the turbine, and portions of the generator may be adapted to rotate independent of the drill string 100. In some embodiments one or more of the generator 203, power source 204, second power source 205, electronic processing device 208, D&I package 207, or some other electrical component, may be rotationally isolated from the drill string 100 as well. In the present embodiment, a jack assembly 301 connects the turbine to the jack element 201 via a gear assembly 209. The gear assembly 209 may couple rotation of the turbine to rotation of the jack element 201. In some embodiments, the gear assembly may have a gear ratio of 20/1 to 30/1.

FIG. 3 discloses that the jack assembly 301 may comprise a shaft 309, turbine 211 and gear assembly 209. The jack element 201 may be disposed on a distal end 302 of the jack assembly 301, may substantially protrude from a working face 303 of the drill bit 104, and may be adapted to move with respect to a body 304 of the bit 104. The bit body 304 may be disposed intermediate a shank 305 and the working face 303. The working face 303 may comprise at least one cutting element 306. In the present embodiment the working face may comprise a plurality of cutting elements 306.

The generator may comprise a plurality of magnets mechanically attached to the shaft and a plurality of coils rotationally fixed to the tool string. As the shaft 309 is spun by the turbine, a output signal may be generated in the coils that travel to the electronic processing device 208. This signal may be reflective of the shaft/jack element's RPM. The RPM measurement may be used to determine a relative position of the shaft 309. Additional, a position feedback sensor 202, which also measures the position of the shaft/jack element, may be in electrical communication with the electronic processing device 208. In some embodiments, the position feedback sensor is in communication with the turbine, gears in the gear assembly, any part of the torque transmitting mechanism, and/or combinations thereof. As the signals from the generator 203 and electronic processing device 208 are received, they may be analyzed together to give an accurate depiction of the jack element's relative position to the drill string 100. Knowledge of the jack element's position with respect to the drill string from the electronic processing device coupled with knowledge of the drill string's position from the D & I may provide a knowledge of the jack element's position with respect to the earth.

In the present embodiment the jack element 201 comprises a primary deflecting surface 1001 disposed on a distal end of the jack element 201. The deflecting surface 1001 may form an angle relative to a central axis 307 of the jack element 201 of 15 to 75 degrees. The angle may create a directional bias in the jack element 201. The deflecting surface 1001 of the jack element 201 may cause the drill bit 104 to drill substantially in a direction indicated by the directional bias of the jack element 201. By controlling the orientation of the deflecting surface 1001 in relation to the drill bit 104 or to some fixed object the direction of drilling may be controlled. In some drilling applications, the drill bit, when desired, may drill 6 to 20 degrees per 100 feet drilled. In some embodiments, the jack element 201 may be used to steer the drill string 104 in a straight trajectory if the formation 105 comprises characteristics that tend to steer the drill string 104 in an opposing direction.

The shaft 309/jack element may be adapted to rotate opposite the drill bit 104. A gear assembly 209 may connect the turbine to the shaft 309. The turbine and/or gear assembly may cause the jack element to rotate opposite the drill string. The shaft 309 may rotate at a first angular velocity, represented at 220, while the drill string may rotate at a second angular velocity, presented at 221. The first and second angular velocities may be substantially equal in magnitude.

FIG. 4 discloses the position feedback sensor oriented adjacent to the shaft 309 below the gear assembly. As the position feedback sensor 202 gathers data, it may produce a signal that may be sent to the electronic processing device 208 through a wire 400 or by other means.

The generator 203 may also be in electrical communication with the electronic processing device 208. The generator 203 may comprise a magnet element 299 and a coil element 298 from which the signal is produced. The electronic processing device 208 may be in electrical communication with a downhole telemetry network. The electronic processing device 208 may also be in electrical communication with the D & I.

FIG. 5 discloses a position feedback sensor 202 with at least two magnetically sensitive components 505, 506. The two magnetically sensitive components 505, 506 may comprise a magnet and/or a hall effect sensor. As the shaft 309 rotates, magnetically sensitive components 506 may pass magnetically sensitive components 505. As it passes, a signal may be generated and sent to the electronic processing device 208.

The position feedback sensor 202 may be resistant to downhole pressures. The position feedback sensor 202 may be encased in a pressure resistant vessel 550 adapted to withstand the pressures inherent in downhole drilling. In other embodiments, the position feedback sensor may be covered in a pressure resistant epoxy.

In some embodiments, a position feedback sensor 202 a may be in communication with the gear assembly 209. In some embodiments, a position feedback sensor 202 b may be in communication with a turbine 211 (as shown in FIG. 3).

FIG. 6 a is a diagram of an embodiment of a waveform created by the generator as the shaft rotates. The waveform displays the rotational position of the shaft 309 compared to time. As the shaft 309 rotates, a relative position of the shaft 309 may be ascertained from the waveform. Using data gathered from the D & I tool, the exact position of the shaft 309 may be determined, giving the exact position of the jack element by comparing the relative position of the shaft 309 and the exact position of the drill string 100.

FIG. 6 b discloses the waveforms from the generator combined with a signal from the position sensor. These signals are displayed as functions of position and time. This consistent periodic spike may calibrate the signal from the generator. Over time, due to heat, mechanical stress, material elastic yields, vibration, and/or pressure, the readings from generator may drift. The position sensor's signal may spike as its components cross once every rotation. In some embodiment, a plurality of position sensors may be used at different azimuths to help calibrate the generator's signal.

FIG. 7 discloses a downhole network 717 that may be used to transmit information along a drill string 100. The network 717 may include multiple nodes 718 a-e spaced up and down a drill string 100. The nodes 718 a-e may be intelligent computing devices 718 a-e, or may be less intelligent connection devices, such as hubs or switches located along the length of the network 717. Each of the nodes 718 may or may not be addressed on the network 717. A node 718 e may be located to interface with a bottom hole assembly 102 located at the end of the drill string 100. A bottom hole assembly 102 may include a drill bit, drill collar, and other downhole tools and sensors designed to gather data and perform various tasks.

As signals from downhole tools are obtained, they may be transmitted uphole or downhole using the downhole network 717. This may assist downhole tools in communicating with each other. The downhole network 717 may be in electrical communication with an uphole computing device 728. The electronic processing device 208 and D&I 207 may be in electrical communication with the downhole network 717.

Transmitting the jack element's orientation signal to the surface may allow drillers to make real time decision and correct drill string trajectories that are off of the desired path before trajectory correction. In some embodiments, the signal may be transmitted wirelessly to off site locations once the signal is at the surface. Such an embodiment would allow drilling experts to position themselves in a central location and monitor multiple wells at once.

FIG. 8 discloses a position feedback sensor 202 with an optical encoder 800. The optical encoder 800 may comprise mirrors 801 and a reader 800. The mirrors 801 may reflect back a signal sent from the reader 800 to determine a rotation position of the shaft 309. The optical encoder 800 may be powered by a downhole electrical source such as the generator 203.

FIG. 9 discloses a position feedback sensor 202 with a mechanical switch 900 adapted to track the position of the shaft 309. As the shaft 309 turns, the mechanical switch 900 may track the position of the shaft 309 by detecting the switch components mechanical contact with each other as they pass.

In some embodiments, the position feedback sensor comprises a resolver, a coil, a magnetic, piezoelectric material, magnetostrictive material, or combinations there.

Whereas the present invention has been described in particular relation to the drawings attached hereto, it should be understood that other and further modifications apart from those shown or suggested herein, may be made within the scope and spirit of the present invention. 

1. A drill string, comprising: a drill bit with a body intermediate a shank and a working face, the working face comprising at least one cutting element; a jack element disposed partially within the drill bit body and substantially protruding from the working face; the jack element being adapted to rotate with respect to the bit body by a turbine disposed within a bore of the drill string; a generator comprising a rotor incorporated into a torque transmitting mechanism linking the turbine to the jack element; wherein when the jack element rotates, at least one waveform is produced in the generator and processed by an electronic processing device to determine the rotational position of the jack element.
 2. The drill string of claim 1, wherein the electronic processing device is incorporated in the drill bit, the drill string, or a remote location in electric communication with a telemetry system of the drill string.
 3. The drill string of claim 1, wherein the torque transmitting mechanism is a shaft that connects the jack element to the turbine.
 4. The drill string of claim 1, wherein the torque transmitting mechanism comprises a gear assembly.
 5. The drill string of claim 4, wherein the gear assembly comprises a gear ratio of 20:1 to 30:1.
 6. The drill string of claim 1, wherein the drill string comprises a position feedback sensor in electrical communication with the electronic processing device.
 7. The drill string of claim 6, wherein the position feedback sensor comprises at least two magnetically sensitive components.
 8. The drill string of claim 6, wherein the position feedback sensor comprises a pressure resistant material.
 9. The drill string of claim 6, wherein the position feedback sensor comprises an optical encoder.
 10. The drill string of claim 6, wherein the position feedback sensor comprises a mechanical switch.
 11. The drill string of claim 7, wherein at least one of the two magnetically sensitive components is disposed on the torque transmitting mechanism.
 12. The drill string of claim 7, wherein at least one of the two magnetically sensitive components is disposed proximate the torque transmitting mechanism.
 13. The drill string of claim 7, wherein at least one of the two magnetically sensitive components comprises a hall effect sensor.
 14. The drill string of claim 7, wherein at least one of the two magnetically sensitive components is powered by a downhole electrical source.
 15. The drill string of claim 6, wherein the position feedback sensor is in communication with a gear of the gear assembly.
 16. The drill string of claim 6, wherein the position feedback sensor is in communication with the turbine.
 17. The drill string of claim 6, wherein the position feedback sensor is in communication with a position of the torque transmitting assembly
 18. The drill string of claim 1, wherein the rotation of the jack element comprises a first angular velocity and a rotation of the drill bit comprises a second angular velocity, wherein the first and second angular velocities are substantially equal in magnitude and opposite in direction.
 19. The drill string of claim 1, wherein the rotational position is a relative rotational position determined by the electronic processing device.
 20. The drill string of claim 1, wherein the electronic processing device is a microcontroller. 